1. Field of the Invention
The present invention relates to a device and method for controlling electric power.
2. Background Information
Electric power source devices for vehicles have been known in which, in a vehicle traveling by selectively using an engine and a motor generator as a drive source, a power source relay for supplying and cutting off electric power to the motor generator from a 42V line power source (battery), which acts as a drive power source to the motor generator, is connected between the 42V line power source and an inverter, and during travel under engine power, the power source relay is turned off within a prescribed period and the open-circuit voltage (OCV) of the 42V line power source is measured (e.g., Japanese Laid-Open Patent Application No. 2003-291754).